Update to contributing guidelines

[AndrewTriesToCode]

Hello all, I've updating the contributing guidelines in the project. See the new guidelines below and let me know if you have any concerns. Thanks!

Contributing

Contributions are always welcome.

New, updated, and improved samples, docs, and tests are always needed.

For small changes and corrections please go ahead and open a pull request.

For more complex changes or new features please file an issue before you open a pull request so we can discuss and plan accordingly.

Regarding new features, the repository prioritizes maintainability, core functionality, and common use-cases. Additional features will be considered on a case-by-case basis.

Authors are encouraged to host their own repositories for functionality outside these guidelines and to submit a pull request adding an appropriate section, description, and link to their repository in to the official docs.